Data centers provide a platform for users to run applications. A data center usually contains a number of computer servers which provide hardware and software resources for storage, management and dissemination of data and information related to the applications. Using these hardware and software resources, data centers may provide elastic services in terms of Infrastructure as a Service (IaaS), Platform as a Service (PaaS), or Software as a Service (SaaS) to users based on user demands.
The servers of the data center may also provide a plurality of virtual machines, one or a subset of which are used to run applications. A virtual machine is an operating system or an application environment that is run within a current operating system on a computer as one of its programs. The selection of virtual machines chosen to run the applications depends on a workload of each of the applications.
The management of both the hardware and software resources of a data center has a significant impact on the cost of operating the data center. The efficient management of the resources of the data center depends on the organization of the resources based on the workloads of the applications.